Existing theoretical models of the potential effects of climate change on vector-borne diseases do not account for social factors such as population increase, or interactions between climate ...variables. Our aim was to investigate the potential effects of global climate change on human health, and in particular, on the transmission of vector-borne diseases.
We modelled the reported global distribution of dengue fever on the basis of vapour pressure, which is a measure of humidity. We assessed changes in the geographical limits of dengue fever transmission, and in the number of people at risk of dengue by incorporating future climate change and human population projections into our model.
We showed that the current geographical limits of dengue fever transmission can be modelled with 89% accuracy on the basis of long-term average vapour pressure. In 1990, almost 30% of the world population, 1·5 billion people, lived in regions where the estimated risk of dengue transmission was greater than 50%. With population and climate change projections for 2085, we estimate that about 5–6 billion people (50–60% of the projected global population) would be at risk of dengue transmission, compared with 3·5 billion people, or 35% of the population, if climate change did not happen.
We conclude that climate change is likely to increase the area of land with a climate suitable for dengue fever transmission, and that if no other contributing factors were to change, a large proportion of the human population would then be put at risk.
Published online August 6, 2002 http://image.thelancet.com/extras/01art11175web.pdf
Background. South Africa (SA)'s high adolescent fertility has been extensively studied. A pregnancy outcome that has not received sufficient attention in research is the causes of death among ...pregnant adolescents. Objectives. To examine levels and causes of adolescent maternal mortality in SA. Methods. A secondary data analysis of Death Notification Forms from 2006 to 2012 was carried out. SA General Household Surveys from 2006 to 2012 were used to ascertain the number of female adolescents in the population. Frequency distributions and life table techniques were employed. Results. An estimated 1 164 deaths have been recorded among pregnant adolescents between 2006 and 2012. Adolescent maternal and pregnancy-related mortality is lower than adult maternal and pregnancy-related mortality. The main causes of death among adolescentswere hypertension (55.6% of all direct causes), abortion (17.6% of all indirect causes) and injuries (48.9% of all indirect causes). The probability of adolescents dying while pregnant without these causes is practically non-existent (range 0.002 - 0.150%). Conclusion. Policies and programmes should prioritise these pregnancy-related causes of death in order to further reduce such deathsamong adolescents in SA.
The aim of this study was twofold, namely to examine (1) the effect of learner misbehaviour on identified symptoms of educator burnout and stress, and (2) the possible association between demographic ...variables and symptoms of educator stress and burnout as a direct result of learner misbehaviour. The quantitative empirical approach was used in this study. A self-reporting questionnaire was completed by 511 educators. The data were analysed by means of frequencies, the Student's t-test and the One-way ANOVA (analysis of variance) statistic. The results are reported against the background of a diagrammatical, enumerative display of the nature and frequency of different types of misbehaviour that the respondents had to address. The results prove that learner misbehaviour in Lesotho has serious negative consequences for a relatively small percentage of respondents. Contrary to the prevailing view in the literature, the data furthermore show that learner misbehaviour in Lesotho more often impacts negatively on male and on experienced educators, than on their female and their less experienced counterparts.
Background. Despite efforts to reduce self-harm mortality, death rates remain high, with almost 12% of all youth deaths in South Africa (SA) attributed to this cause. There are gendered differences ...in causes of death among youth, but little is known about the sex-specific risk factors.Objective. To identify the levels and sex-specific determinants of self-harm mortality among youth in SA.Methods. This was a cross-sectional study of SA death notification forms from 2006 to 2014. Descriptive and analytical statistical techniques were used, including cause-specific mortality rates, proportional mortality ratios and logistic regression models.Results. A total of 1 122 youth (15 - 24 years of age) deaths due to self-harm causes were reported over the study period, during which rates of self-harm mortality increased. More deaths of males (n=818) than females (n=304) were reported. Almost 60% of deaths (p<0.05) were of 20 - 24-year-olds, and 46.4% (p<0.05) of those who died had a secondary education. Almost 10% of females (p<0.05) were pregnant at the time of death. Hanging was the most common type of self-harm mortality among males (79.2%) and females (49.3%). While 11.0% (n=90) of self-harm deaths of males were due to poisoning, more females used this method (39.8%, n=121). The probability of self-harm mortality for males increased according to certain provinces of residence. For females the odds were higher for those who were pregnant (odds ratio (OR) 1.3; p<0.05) and non-South African (OR 1.7; p<0.05) and had secondary education (OR 1.4; p<0.05).Conclusions. The study showed gender differentials in the determinants of self-harm mortality among youth in SA. For this reason, uniform approaches to awareness campaigns need to be altered to address the specific needs of youth. While males have higher rates than females, the prevalence of self-harm mortality in pregnant females is of concern and needs to be addressed specifically, as it relates not only to suicidal ideation and behaviour but also to youth sexual and reproductive health programmes in the country.Â
BACKGROUND. A universal goal of public health is to ensure that adolescents have a healthy transition to adulthood. In developing countries, a host of social, economic and political factors inhibit ...this from happening. The results of these challenges include an increasing disease prevalence among an age group (10 - 19-year-olds) that should be healthy.OBJECTIVES. The purpose of this study is to identify the most prevalent diseases and assess the relationship between disease and grade repetition among adolescents in South Africa (SA), and to assess the impact of disease on grade repetition.METHODS. Data from the SA General Household Surveys (2009 - 2016) were analysed, and both adolescent (10 - 19 years) sexes from all geographical and racial groups were included. Frequencies, percentages and rates of infectious, non-communicable diseases (NCDs) and mental health outcomes were estimated. The relationship between disease and grade repetition was determined using logistic regression.RESULTS. Infectious diseases, NCDs and mental illnesses are increasing in adolescents over time. In urban areas, rates of NCDs are higher than those of infectious diseases, while in rural areas a high burden of infectious disease persists. Among adolescents who repeated a grade, 7.07% had an infectious disease. In addition, infectious disease (odds ratio (OR) 1.17, p<0.05), younger adolescents, 15 - 19-year-olds (OR 1.52, p<0.05) and urban residence (OR 1.12, p<0.05) are associated with increased likelihood of grade repetition.CONCLUSION. Policies and programmes in SA which address the health of adolescents need to be more aware of the disease prevalence among school pupils in the country. Prolonged disease occurrences are contributing to the slow school progression and eventual matriculation of pupils.
Background. International guidelines have discouraged screening of young women under the age of 21 for cervical cancer. However, a high screening rate is still evident among adolescent girls in ...Lesotho. Objective. To explore the levels and determinants of cancer screening among adolescent girls in Lesotho. Methods. This cross-sectional study used secondary data from the 2014 Lesotho Demographic and Health Survey collected from 1 542 adolescent girls aged 15 - 19 years. Descriptive statistics, the chi-square test and a binary logistic regression model were used to analyse the data. Results. Despite recommendations that adolescents should not screen for cervical cancer, results show that 15% of adolescent girls in Lesotho attend screening services. Adolescent girls from rural areas are less likely to screen than those from urban areas (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.07 - 0.68; p=0.009). Marital status and level of education were significantly associated with cervical cancer screening among respondents; however, age at first sex was not statistically associated with screening among adolescent girls. Conclusion. With reference to international guidelines, the screening rate for cervical cancer is high among adolescents in Lesotho. Future studies should focus on why adolescents in Lesotho still screen for cervical cancer despite international recommendations discouraging screening before the age of 21.
Background. Several drivers of risky sexual behaviour are known, although research has not yet examined the relationship between experiences of sexual harassment at school and risky sexual behaviours ...among adolescents. Objective. To examine the association between peer- and teacher-perpetrated sexual harassment and risky sexual behaviours among adolescents in South Africa. Methods. Cross-tabulations and logistic regression models were fitted to data from 219 456 school-going adolescents (aged 10 - 19 years) who participated in the fourth South African National HIV, Behaviour and Health Survey (2011/2012). The outcomes were lack of condom use during last sexual activity and multiple sexual partnerships. Results. Of the respondents who had experienced sexual harassment by peers, 27.27% did not use a condom during their last sexual activity and 41.67% reported having had multiple sexual partnerships. Of the respondents who had experienced sexual harassment by a teacher, 5.56% reported to have had multiple sexual partnerships in the study period. Results show that respondents who had experienced peer-perpetrated sexual harassment were more likely to not have used a condom during their last sexual activity (odds ratio (OR) 1.08; 95% confidence interval (CI) 1.04 - 1.11), as were those who had experienced teacher-perpetrated sexual harassment (OR 1.37; 95% CI 1.32 - 1.43). Conclusion. A substantial number of school-going adolescents were found to have experienced sexual harassment and engaged in risky sexual behaviours. Sexual harassment at school should be considered as part of programmes aimed at addressing risky sexual behaviours among adolescents.
Background. The level of unintended pregnancies among teenage girls in South Africa (SA) has remained a public health concern. However, studies and interventions generally do not consider young men’s ...involvement in teenage pregnancies. Objective. To investigate the sociodemographic and sexual behaviour characteristics of young men who have impregnated at least one teenage girl. Methods. The study used data from the Centre for Justice and Crime Prevention (2009), which included responses from young men (aged 12 - 22 years) across all SA provinces. Univariate and bivariate analyses and binary logistic regression were performed. Results. The results showed that 93.2% of the sample had ≥2 lifetime sexual partners, 22.4% rarely used condoms and 11.5% had never used condoms. Teenage pregnancy incidence was ≥35% in all provinces except Gauteng and the Western Cape. The likelihood of being involved in a teenage pregnancy was higher among respondents who reported having ≥2 lifetime sexual partners (odds ratio (OR) 2.510; 95% confidence interval (CI) 0.43 - 14.77). Respondents with a higher education were less likely to be involved in a teenage pregnancy (OR 0.819; 95% CI 0.36 - 1.84) than those with a lower education (OR 1.219; 95% CI 0.59 - 2.50). Conclusion. Engaging in multiple sexual partnerships could increase the vulnerability of young people to sexually transmitted infections or teenage pregnancies. Initiatives to create awareness among SA youth regarding the consequences of sexual behaviour are recommended, with a specific focus on addressing young men’s involvement in teenage pregnancy.
The automated functional and performance analysis of communication systems specified with some Formal Description Technique has long been the goal of telecommunication engineers. In the past SDL and ...Petri nets have been the most popular FDTs for the purpose. With the growth in popularity of UML the most obvious question to ask is whether one can translate one or more UML diagrams describing a system to a performance model. Until the advent of UML 2.0, that has been an impossible task because the semantics were not clear. Even though the UML semantics are still not clear for the purpose, using ITU recommendation Z.109 with UML 2.0 now released, we describe in this paper a methodology and tool called proSPEX (
protocol
Software
Performance
Engineering using
XMI) for the design and performance analysis of communication protocols specified with UML.
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